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Firestop Slide Show 1 of 10 Basics

Firestop Slide Show 2 of 10 Code

Firestop Slide Show 3 of 10 No Seal

Firestop Slide Show 4 of 10 Deemed-to-comply

Firestop Slide Show 5 of 10 Misinstalled

Firestop Slide Show 6 of 10 Re-entered

Firestop Slide Show 7 of 10 Faulty Spec.

Firestop Slide Show 8 of 10 Proper Firestops

Firestop Slide Show 9 of 10 Test

Firestop Slide Show 10 of 10 Smoke and Trays

Sample Firestop Listing

Kitchen Exhaust Cleaning; Boiling-Hot Pressure Washing

ULC           UL

T O S

(Theory of Survival)

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New Links!

I had some USNRC links here, but these were removed by the USNRC from their site. For 'Pro-Foam' drivel, contact the vendors, the USNRC or NEI. I like to present both sides of issues, but since the NRC retraction, I'm left with the links below.

Nuclear Awareness Project: Flammable 'Firestops' Used in CANDU Reactors

Durham Nuclear Awareness: "Inadequate Fire Protection at Nuclear Stations"

Silicone Foam (sometimes referred to as 'black gold' in the nuclear industry) represents the epitome of moral and ethical dilemmas in firestopping. It is the result of a desk idea, spawned by a manufacturer's understandable desire to find applications to market his basic 'bread-and-butter' substance of silicone, regardless of the particular form it may be supplied in. That, in itself is not a bad thing. By comparison, the dairy industry too is understandably glad about every new type of cheese product food technicians may concoct. The silicone foam manufacturer's aim was exclusively (and understandably) to sell silicone. Silicone is a common building product and has also found use in firestop caulking and even in cosmetic surgery. This aim was preserved despite clear and painfully obvious evidence of the striking unsuitability of the product for the purpose of firestopping. No purpose-designed firestop in recorded history is so dependent upon furnace insulation to actually perform the firestopping function, as silicone foam. Its use, when sandwiched between ceramic fibre panels or packing is quite superfluous, but at least it's expensive and adds a tremendous amount of smoke and keeps smoldering internal fires for up to half a day after an external fire begins near such a silicone foam seal. This striking logic (!?) has brought it a high degree of marketing success in the North American nuclear power generation market. Silicone foam has been widely used for firestopping through-penetrations in power plants. Most of the seals have been misinstalled and remain that way. Silicone foam has been manufactured and sold for firestopping purposes by three companies in North America plus a number of contractors who may or may not have added certain ingredients and called the resulting product their own. Silicone foam is essentially similar to silicone caulking, except that it comes in two liquid parts, which are mixed together in equal proportions. Silicone consists of rubber, which is thickened with amorphous silica fume, which is an inorganic, white, finely divided mineral dust. Silica fume is available in fineness between 50 and 380m² of surface area per gram of powder. That is very fine dust indeed. Coarser versions of the fume are also used as addmixtures in cementitious products. In silicone compounding, each of the particles is then surrounded by rubber. In a fire, the organic rubber burns off, creating an enormous amount of highly corrosive and extremely toxic smoke and leaves the silica and carbon ash behind. The idea is to dam up the opening rather vigilantly, because the mixture enters the opening in a syrup consistency. Herein lies the folly of the 'desk idea'. "Look! It can spread between cables!" (and leave huge voids and never quite fill the hole, on and on and on) During the 'snapping' or curing process, hydrogen gas is evolved and released, which bubbles up while the rubber vulcanises, or changes form, from liquid to solid. This is why the instructions tell you to work in well ventilated areas. Explosions have resulted from disregarding this little feature. Generally, the opening should be poured 1/3 full and the rest is intended to fill up due to the expansion of the foam. One is supposed to work in small "lifts" (small quantities of the mixture poured at a time) to avoid bigger problems with uncontrolled expansion and lack of spreading (where reality meets marketing/propaganda) between penetrants. Because of the organic content inherent in the foam, deepseated internal fires result from heat exposure. This has been documented in numerous fire tests both by public utilities and the private sector. Many of these documents are available from the USNRC. This is why the foam is typically sandwiched inside of ceramic fibre boards (which would easily pass the entire test without the foam in the middle, which acts as a detriment resulting in the use of supplied air breathing apparatus for anyone nearing the test specimen in a laboratory where this material is tested as a firestop in a mock-up floor slab or wall), which are used in furnace insulation, or refractory applications. Notice something? Furnace insulation. You have to protect this foam with stuff that can last for months in insulating a blast furnace. Why call this a firestop product apart from creative marketing? Nestled inside of a ceramic fibre, or other noncombustible board sandwich, the foam is not as much of a detriment, though a large fuel contributor to the raging fire. When fire-testing a cable penetration seal at a laboratory, usually the worst of the smoke comes from the burning cable jacketing. This ceases typically after 1/2 hour. But when the seal contains silicone foam, there is a constant stream of smoke throughout the test duration, as well as ash rain all over the place, in labs, which do not vent their smoke immediately outside of the building (Believe it or not, this does occur!). This smoke generation disadvantage is offset by the high cost. (Homer lives!) Silicone foam is probably the most misinstalled product on the market, often cited in reportable events with the United States Nuclear Regulatory Commission. The primary reason for this is a complete absence of bounding. Manufacturers of silicone foam have never held back on their testing details, which always included ceramic fibre sandwich construction details to make sure that this product actually passes the test. The deep seated internal fires cited by the USNRC have been quantified in Canada to last up to 9 hours in an 8" thick seal. The USNRC actually stated in writing, that after a fire, fire fighters are supposed to remove still burning foam from engaged seals in order to prevent further flare-ups and burn-throughs during the recovery period following a fire. This was the USNRC's spinmeistering response to the question of how plants were expected to deal with the burn-through issue, particularly in the many unbounded seals. If installed as per manufacturer's instructions and bounded, as in sandwiched inside of furnace insulation boards, the foam simply glows out after about 9 hours (whilst producing lots of killer smoke). Silicone foam creates more smoke than you can possibly imagine. Have a look at the smoke issues on this page. On that page, you can see the effects of two feet of burning cable jacketing. Relate and quantify that burning cable jacketing in cubic inches of organic matter. Compare what you get against say a 10 square foot hole (which is not uncommon in an industrial setting), sealed with foam, 8" deep. That's a lot of rubber to burn. Part of the trouble in the nuke plants is that the foam manufacturers themselves did not qualify their product for use in all the various penetration seal configurations in all the plants. The manufacturers' tests are not enough. There are many holes, bigger, and with different penetrants, which are not bounded by the manufacturers' tests. Because certification is optional in North American nuclear plants, contractors have run their own tests outside of certification regimes. They could even write their own test procedures (!!) and build their test specimens unobserved. This would be illegal in normal buildings all over North America. But it is still OK in nuke plants. To make matters worse, plants have illegally traded test reports with one another and used them to justify installed seals in their plants. The NRC considers all silicone foam to be pretty much identical and does not concern itself with this fact, which violates the rights of the contractors (one, two, three: "Aaaaaw!") to their own test reports, which wouldn't be acceptable to any building inspector to begin with. The general operability, apart from standard bounding issues, of a silicone foam seal, depends on internal pressure. The (combustible/explosive) hydrogen gas, which forms the bubbles, as well as a health and explosion hazard during installation in confined spaces, as cautioned on the product containers and the MSDS, generates an outward pressure inside of the vulcanising and the vulcanised foam. The pressure (not adhesion) is what is supposed to hold the seal in place. Despite any claptrap about "closed-cell" foams, hydrogen gas (H2) has a tendency to escape over time, which renders the installed seal inoperable. The seal-internal foam pressure that was there during the fire test, which is the sole event, which qualifies the material for this use) is thus no longer there or as high, months after the installation, because of the escape of hydrogen gas, which continues after the installation, during which time it is a different hazard. This is particularly noticeable in seals, which are (illegally and frequently) not covered by the ceramic fibre boards, which are supposed to be on both sides of wall holes and the bottom side of floor holes, at least in bounded openings, as the manufacturers rightly instruct users, a lot of whom delight in ignoring such details for expediency and economic reasons. Shrinkage thus can occur to the point where, in a vibrating process pipe penetration seal, the rubber ring 'firestop' can be found jiggling along the pipe, several feet away from the hole it was originally poured into. Still, whatever the problems are with this product, one can meet code using silicone foam by bounding. Most of the problems have happened where bounding was ignored, such as North America's nuclear industry. This has nothing to do with the manufacturers. It has everything to do with the fact that the local building inspectors have no jurisdiction in those plants and that the quality control regime focused on things that had nothing to do with whether the seals themselves were actually bounded and in compliance with the building code. Attacks upon the use of silicone foam have focused on its combustibility and fuel contribution because it was believed that the issue of bounding would not be understood (Actually, few people care to listen long enough, which protects the status quo here. The fact remains that few people have the remotest concern for fire protection.). Other fire protection products have been used in many places, which are not strictly non-combustible. However, few if any fire protection products generate as much toxic and corrosive smoke and have as many inherent problems as silicone foam. Since the attack upon the use of foam was based upon its combustibility, those who sought to protect the pitiful status quo in places where silicone foam was used, were able to dispense with the argument on the basis that combustibility is not relevant in firestopping. A lot of this can be based on the combustibility of paints and caulking products, which are often components in firestopping. The issue of bounding thus never truly arose with press or much congressional attention. Therefore, one can still find a lot of nuclear silicone foam penetration seals, without any of the mandatory ceramic fibre board covers in place, which are deemed a nuisance for re-entry. A morally bankrupt and indicative rebuff of such combustibility arguments came via the use of the term "ablative". What this means is that an ablative product is meant to disintegrate in time, say 3" per hour (This is a great way to sidestep the fact that the non-combustible covers, a legal requirement, are missing in a lot of plants.). Thus, the idea behind the use of ablative products is to put so much of it in the way of the fire, that one simply does not run out of time. Hence, one may argue that if this material burns well (and it does - in fact you can extinguish a burning lump of silicone foam several times and will find that it simply starts up again, that is to say, the deepseated internal fire gets back outside), it simply does what it is supposed to do - ergo morally indicative. Ablative sounds so nice and technical though. 'Burns like hell' sounds a lot less attractive than 'ablative'. Just like 'meat' sounds a lot more palatable than 'dead flesh'. 'Veal' sounds a lot better on a menu than 'flesh of dead baby cows'. By the same token, when you examine a very small piece of the foam and subject it to a lighter flame, you may find it to be 'self-extinguishing'. But such slight of hand tricks have little bearing on reality in a building fire or a fire test. In reality, it is the synergy of using large quantities of the silicone foam, with penetrants, which carry heat to the centre of the penetration seal, that creates big problems, which are not easily detected in bench-scale testing. In the historical context, silicone foam came AFTER MCT. MCT set a nice, high price level, beneath which silicone foam could comfortably slip at about $300.00 per square foot installed in industrial settings (compared to about $600.00 per square foot installed in Canadian nuclear power plant settings). MCT actually, is a lot cheaper than silicone foam, when one considers all of the problems, the retooling, the NRC reportable events, the fire watches and their drug use (see many 'reportable events'), etc. Ironically, early users of silicone foam thought the high cost of MCT  (in the initial purchase price) to be laughable, compared to the slick new method. Check firestop mortars, and you might wonder why one would even consider the use of silicone foam in these large penetrations. Mortars are typically well paid @ around $120.00 per square foot installed. They're non-combustible. Silicone Foam is often dispensed in 'Semkits' (hand-held cartridges, which contain both components). A plunger ruptures the membrane in the kit and is then used to mix the two components. It is clearly advisable to dispense the mixed liquid quickly, before the expansion takes place (think about it). Another method is a two part pump, where the components are mixed at the application nozzle.

Here is a picture of a two-component pump used to deliver components A and B. Mixing takes place at the nozzle.

'Foamfixer'

The current status quo concerning the use of this product in nuke plants and other places establishes some amazing economics. It can take truckloads of raw foam to seal up a whole plant. We are talking about millions of dollars just in material. The labour too is a huge factor. Removing polyurethane foam from existing penetrations seals has clocked in at around 3 man-hours per cubic foot removed. If you remove it, you still have to replace it. Some of the nuke contractors have also altered the foam somewhat by adding other ingredients, such as more silica fume etc. Now how will you bound a seal, which contains references to two or three different contractors' test reports, when you may have used only one of them? Perhaps one contractor repaired another contractor's seal (bearing in mind that the low bid gets the job, whether the seals are bounded afterwards or not, which results in the use of a lot of fire watches - people armed with portable fire extinguishers, who are paid to look at seals around the clock because those silicone foam penetrations seals are not bounded). Or perhaps the plant itself bought Semkits off the shelf to repair (using plant forces) a seal from a contractor whose foam may have been slightly different. Certainly the bounding is highly questionable then - except to the NRC where anything goes when it comes to this. In our Canadian nuke plants, contractors as well as plant staff made no effort to provide any bounding information. Subsequently, US specialists have been hired to justify bounding on the basis of US methods, which are described herein. While the Canadian regulator SAYS that plants shall meet the National Building Code of Canada and the National Fire Code of Canada, both of which require certification, the essential legal requirement of certification for penetrations seals in Canadian nuclear generating stations has been omitted, which is the reason why unbounded seals are acceptable in Canadian nuclear plants. To make all this malarki look good, our regulator insists that an independent fire protection engineer review the plant and make recommendations where necessary. The regulator then gets a report and follows up with the plant to see that the deficiency list is addressed, eventually. Thus industry and regulator protect one another. When one looks only at the bottom line costs, it is easy to see why people simply want the issues to go away and will go to great lengths to avoid it altogether. They have well written documentation to make it all look good, which I would defy people to stay awake long enough to read, the technical merit of which is easily dismissed by the contents of this page alone and the back-up that supports it, such as the 'Brown Report' from the City of Pickering, Regional Councillor Maurice Brenner, Ward 1. As for new installations, some folks will not be confused by facts and continue to use this product. Why anyone would do that considering the available alternatives and the obvious downsides is difficult to understand, but I strongly suggest clergy or therapy to such unfortunate individuals. The product continues to be installed in varying spurts all over North America - sometimes in large quantities bound for strange places! Musings about the reason for this have included that perhaps the high price convinced users that it just HAS to be good stuff, no matter what, as well as perhaps the amusement factor of the installer. When you mix the two components together, they bubble and crackle and expand. That's really cool to watch. I have seen anatomical shapes recreated with silicone foam in some offices, which are rather amusing. No other firestop product I know of has that particularly entertaining feature. Even pillows don't come close. When such slight-of-hands tricks as the foam in the disposable cup on your desk are demonstrated on the buyer's desk, it slightly reminds one of small balls sent aloft by vacuum cleaners sold door to door, or perhaps of people attracted by small, shiny objects. Go figure.

BACK to Products

Firestop Page

Main Page

Contact

Main Site

Firestop Site

Code Evaluations AVAILABLE!

Glossary of Fire Protection Terms

3M Fire Barriers

Vectorising Drawings and Maps; Paper to CAD

Circuit Integrity Fireproofing

Bounding

Code Req's for Firestops

Essay on Performance Based Codes

Master Spec. Section 07840 Firestopping

Related Sections to 07840

Penetration Seal Drawings

Building Joint Drawings 1

Building Joint Drawings 2

Building Joint Drawings 3

History of Firestops in North America

Warnock Hersey Experience

Firestop Trade Jurisdiction

Achim Hering Bio

Man Made Mineral Fibres

Fire Protection Industry Links

Firestop Products and Equipment

Firestop Mortar

Firestop Silicone Foam

Intumescent Products

Endothermic Products

Insulation Products

Caulking & Paint Firestops

Firestop Pillows

Firestop Devices

Firestop Slide Show 1 of 10 Basics

Firestop Slide Show 2 of 10 Code

Firestop Slide Show 3 of 10 No Seal

Firestop Slide Show 4 of 10 Deemed-to-comply

Firestop Slide Show 5 of 10 Misinstalled

Firestop Slide Show 6 of 10 Re-entered

Firestop Slide Show 7 of 10 Faulty Spec.

Firestop Slide Show 8 of 10 Proper Firestops

Firestop Slide Show 9 of 10 Test

Firestop Slide Show 10 of 10 Smoke and Trays

Sample Firestop Listing

Kitchen Exhaust Cleaning; Boiling-Hot Pressure Washing

ULC           UL

T O S

(Theory of Survival)

DIBt

TU Braunschweig iBMB

CONTACT

1